which of these heroes are easiest to gear and pass cosmic trial?

Hi all,

i am a returning player(only abt 30+ login days clocked) and have time only to focus on a hero to play.
As such, out of these heroes which i have, which one is recommended/easier for me to pass cosmic trial with minimun gear?

Loki, Hulk, War Machine, Emma Frost, Iceman

note: *I dont have popular artifacts like gem of kurse, gorilla necklace etc. *
EDIT: " it was ICEMAN, not Ironman, my typo mistake. Thanks for all the input!"